LPS levels in root canals after the use of ozone gas and high frequency electrical pulses

Abstract The present study aims to verify the effect of ozone gas (OZY® System) and high frequency electric pulse (Endox® System) systems on human root canals previously contaminated with Escherichia colilipopolysaccharide (LPS). Fifty single-rooted teeth had their dental crowns removed and root lengths standardized to 16 mm. The root canals were prepared up to #60 hand K-files and sterilized using gamma radiation with cobalt 60. The specimens were divided into the following five groups (n = 10) based on the disinfection protocol used: OZY® System, one 120-second-pulse (OZY 1p); OZY® System, four 24-second-pulses (OZY 4p); and Endox® System (ENDOX). Contaminated and non-contaminated canals were exposed only to apyrogenic water and used as positive (C+) and negative (C-) controls, respectively. LPS (O55:B55) was administered in all root canals except those belonging to group C-. After performing disinfection, LPS samples were collected from the canals using apyrogenic paper tips. Limulus Amoebocyte Lysate (LAL) was used to quantify the LPS levels, and the data obtained was analyzed using one-way ANOVA. The disinfection protocols used were unable to reduce the LPS levels significantly (p = 0.019). The use of ozone gas and high frequency electric pulses was not effective in eliminating LPS from the root canals

Effects of ozone and photo-activated disinfection against Enterococcus faecalis biofilms in vitro

Objectives: The purpose of this study was to compare the antibacterial effects of gaseous ozone (O-3) and photo-activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: Sixty-five human mandibular premolars with straight root canals were selected. After root canal preparation, the samples were sterilized and placed into eppendorf tubes with 1 mL brain heart infusion broth containing 1.5 x 10(8) colony-forming units (CFUs)/mL of E. faecalis. The contaminated samples were then divided into four groups (n = 15) according to the disinfection method used: Group 1, Saline (positive control); Group 2, NaOCl (negative control); Group 3, Gaseous O-3; and Group 4, PAD. Three non-contaminated teeth were used to control the infection and sterilization process. The CFUs were counted and the data were analyzed statistically. Results: There was a statistically significant difference between the experimental and control groups (P 0.05). Conclusion: Both PAD and gaseous O-3 have a significant antibacterial effect on infected root canals. However, 2.5% NaOCl was superior in terms of its antimicrobial abilities compared with the other disinfection procedures